Chapter 7 - Energy-Related Carbon Dioxide Emissions
| In 2005, non-OECD emissions of carbon dioxide exceeded OECD emissions
by
7 percent. In 2030, carbon dioxide emissions from the non-OECD countries
are projected to exceed those from the OECD countries by 72 percent. |
Carbon dioxide is the most abundant anthropogenic (human-caused) greenhouse
gas in the atmosphere. Atmospheric concentrations of carbon dioxide have
been rising at a rate of about 0.6 percent annually in recent years, and
that growth rate is likely to increase. As a result, by the middle of the
21st century, carbon dioxide concentrations in the atmosphere could be
double their pre-industrialization level (see "What Will It Take To Stabilize Carbon Dioxide Concentrations?").
Because anthropogenic emissions of carbon dioxide result primarily from
the combustion of fossil fuels for energy, world energy use has emerged
at the center of the climate change debate. In the IEO2008 reference case,
world carbon dioxide emissions are projected to rise from 28.1 billion
metric tons in 2005 to 34.3 billion metric tons in 2015 and 42.3 billion
metric tons in 2030.19
From 2004 to 2005, total energy-related carbon dioxide emissions from the
non-OECD countries grew by 6.6 percent, while emissions from the OECD countries
grew by less than 1 percent. Consequently, annual emissions from the non-OECD
countries currently exceed total annual emissions from the OECD countries,
and the difference is growing (Figure 75). In addition, the projected average
annual increase in non-OECD emissions from 2005 to 2030 (2.5 percent) is
five times the increase projected for the OECD countries (0.5 percent).
In 2030, non-OECD emissions, projected at 26.8 billion metric tons, exceed
the projection for OECD emissions by 72 percent. The IEO2008 reference
case projections are, to the extent possible, based on existing laws and
policies. The projections for carbon dioxide emissions could change significantly
if existing laws and policies aimed at reducing the use of fossil fuels,
and thus greenhouse gas emissions, changed.
The relative contributions of different fossil fuels to total energy-related
carbon dioxide emissions have changed over time. In 1990, emissions from
the combustion of liquids and other petroleum made up an estimated 42 percent
of the world total; in 2005 their share was 39 percent; and in 2030 it
is projected to be 35 percent (Figure 76). Carbon dioxide emissions from
natural gas combustion, which accounted for 19 percent of the total in
1990, increased to 20 percent of the 2005 total. That share is projected
to stabilize at between 20 and 21 percent from 2005 to 2030.
Coal’s share of world carbon dioxide emissions grew from 39 percent in
1990 to 41 percent in 2005 and is projected to increase to 44 percent in
2030. Coal is the most carbon-intensive of the fossil fuels, and it is
the fastest-growing energy source in the IEO2008 reference case projection,
reflecting its important role in the energy mix of non-OECD countries—especially
China and India. In 1990, China and India together accounted for 13 percent
of world carbon dioxide emissions; in 2005 their combined share had risen
to 23 percent, largely because of strong economic growth and increasing
use of coal to provide energy for that growth. In 2030, carbon dioxide
emissions from China and India combined are projected to account for 34
percent of total world emissions, with China alone responsible for 28 percent
of the world total.
The Kyoto Protocol, which requires participating “Annex I” countries to
reduce their greenhouse gas emissions collectively to an annual average
of about 5 percent below their 1990 level over the 2008-2012 period, entered
into force on February 16, 2005. Annex I countries include the 24 original
OECD countries, the European Union, and 14 countries that are considered
“economies in transition.”20 As of December 3, 2007, 174 countries and
the European Commission had ratified the Kyoto Protocol; however, only
the Annex I countries that have ratified the Protocol are obligated to
reduce or limit their carbon dioxide emissions. The United States has not
ratified the Protocol; and although both China and India have ratified
it, neither is subject to emissions limits under the terms of the treaty.
Although the Protocol is technically “in force,” it would have an effect
on only one year of the IEO2008 forecast,
namely, 2010. The IEO2008 projections do not explicitly include the impacts
of the Kyoto Protocol, because the treaty does not indicate the methods
by which ratifying parties will implement their obligations.
Further, although some countries have passed laws intended to implement
the goals of the Kyoto Protocol, it is difficult to interpret those laws
in the IEO2008 reference case. Many of the Kyoto goals are being met by
“Kyoto mechanisms,” such as reforestation, which are not reflected in the
projections. Additionally, greenhouse gases other than carbon dioxide often
are the least expensive to reduce, and those reductions may account for
a larger proportion of some countries’ Kyoto goals. In the IEO2008 projections
only energy-related carbon dioxide emissions are calculated; estimates
of other greenhouse gas emissions are not included.
Finally, the participants have been unable to agree on a second commitment
period or on any actions that might occur after 2012. Until those issues
are resolved, it will be difficult to project the effects of the Kyoto
Protocol through 2030.21
There are signs that concerns about global climate change are beginning
to affect the world fuel mix. In recent years, many countries have begun
to express new interest in expanding their use of non-carbon-emitting nuclear
power, in part to stem the growth of greenhouse gas emissions. The IEO2008 reference case projection for electricity generation from nuclear power
in 2030 is almost 4 percent higher than the IEO2007 projection, which in
turn is 10 percent higher than the IEO2006 projection. The changes reflect
a generally more favorable perception of nuclear power as an alternative to carbon-producing fossil
fuels for electricity generation.
Reference Case
Carbon Dioxide Emissions
In the IEO2008 reference case, world energy-related carbon dioxide emissions
are projected to grow by an average of 1.7 percent per year from 2005 to
2030 (Table 12). For the OECD, annual increases in carbon dioxide emissions
are projected to average 0.5 percent, from 13.6 billion metric tons in
2005 to 14.4 billion metric tons in 2015 and 15.5 billion metric tons in
2030.
The highest rate of increase in annual emissions of carbon dioxide among
the OECD countries is projected for Mexico, at 2.1 percent per year (Figure
77). Mexico is projected to have the highest GDP growth rate among the
OECD countries, and much of its growth is expected to come from energy-intensive
industries. For all the other OECD countries, annual increases in carbon
dioxide emissions are projected to average less than 1.5 percent. South
Korea, which still is industrializing, is the only OECD country other than
Mexico for which the average is projected to be greater than 1 percent.
Japan’s emissions are projected to decrease by an average of 0.2 percent
per year from 2005 to 2030, and for OECD Europe an average annual increase
of 0.4 percent per year is projected.
Although the United States has not ratified binding emissions constraints,
recent changes in U.S. environmental laws and regulations (in addition
to other factors) have lowered the projections for carbon dioxide emissions
relative to earlier estimates.22 In the IEO2007 reference case, U.S. emissions
were projected to grow by an average of 1.1 percent per year from 2005
to 2030. In the IEO2008 reference case, in contrast, the projected annual
growth rate is 0.5 percent over the same period, leading to a 14-percent
lower projection for energy-related carbon dioxide emissions in 2030 in IEO2008 compared with IEO2007 (Figure 78).
For the non-OECD countries, total carbon dioxide emissions are projected
to average 2.5-percent annual growth (Figure 79). The highest growth rate
among the non-OECD countries is projected for China, at 3.3 percent annually
from 2005 to 2030, reflecting the country’s continued heavy reliance on
fossil fuels, especially coal, over the projection period. China’s energy-related
emissions of carbon dioxide are projected to exceed U.S. emissions by almost
15 percent in 2010 and by 75 percent in 2030. The lowest growth rate among
the non-OECD countries is projected for Russia, at 0.9 percent per year.
Over the projection period, Russia is expected to expand its reliance on
indigenous natural gas resources and nuclear power to fuel electricity
generation, and a decline in its population is expected to slow the overall
rate of increase in energy demand.
By fuel, world carbon dioxide emissions from the consumption of liquid
fuels and other petroleum are projected to grow at an average annual rate
of 1.2 percent from 2005 to 2030. The average growth rates for the OECD
and non-OECD countries are projected to be 0.3 percent and 2.2 percent
per year, respectively (Figure 80). The highest rate of growth in petroleum-related
carbon dioxide emissions is projected for China, at 3.5 percent per year,
as its demand for liquid fuels increases to meet growing demand in the
transportation and industrial sectors. The United States is expected to
remain the largest source of petroleum-related carbon dioxide emissions
throughout the period, with projected emissions of 2.8 billion metric tons
in 2030—still 34 percent above the corresponding projection for China.
Carbon dioxide emissions from natural gas combustion worldwide are projected
to increase on average by 1.7 percent per year, to 8.7 billion metric tons
in 2030, with the OECD countries averaging 1.0 percent and the non-OECD
countries 2.4 percent (Figure 81). Again, China is projected to have the
most rapid growth in emissions, averaging 5.5 percent annually; however,
China’s emissions from natural gas combustion amounted to only 0.1 billion
metric tons in 2005, and in 2030 they are projected to total only 0.4 billion
metric tons, or less than 5 percent of the world total. The growth in U.S.
emissions from natural gas use is projected to average 0.1 percent per
year, but the projected level of 1.2 billion metric tons in 2030 is triple
the projection for China.
Total carbon dioxide emissions from the combustion of coal throughout the
world are projected to increase by 2.0 percent per year on average, from
11.4 billion metric tons in 2005 to 18.8 billion metric tons in 2030. Total
coal-related emissions from the non-OECD countries have been greater than
those from the OECD countries since 1987, and in 2030 they are projected
to be more than 2.5 times the OECD total (Figure 82), in large part because
of the increase in coal use projected for China and India. Together, China
and India account for 79 percent of the projected increase in the world’s
coal-related carbon dioxide emissions from 2005 to 2030. For China alone,
coal-related emissions are projected to grow by an average of 3.2 percent
annually, from 4.3 billion metric tons in 2005 to 9.6 billion metric tons
(51 percent of the world total) in 2030. India’s carbon dioxide emissions
from coal combustion are projected to total 1.4 billion metric tons in
2030, accounting for more than 7 percent of the world total.
Carbon Dioxide Intensity Measures
Emissions per Dollar of GDP
In all countries and regions, energy-related carbon dioxide intensities—expressed
in emissions per unit of economic output—are projected to improve (decline)
over the projection period as all world economies continue to use energy
more efficiently. In 2005, estimated carbon dioxide intensities were 461
metric tons per million dollars of GDP in the OECD countries and 529 metric
tons in the non-OECD countries (Table 13).23
Fossil fuel use in the non-OECD countries is projected to increase strongly
over the projection period; however, their economic growth is expected
to be even stronger. As a result, non-OECD carbon dioxide intensity is
projected to decline by an average of 2.6 percent per year, from 529 metric
tons per million dollars of GDP in 2005 to 274 metric tons per million
dollars of GDP in 2030. In particular, China, with a relatively high projected
rate of growth in emissions (3.3 percent per year), has an even higher
projected growth rate for GDP (6.4 percent). As a result, its emissions
intensity falls from 693 metric tons per million dollars in 2005 to 334
metric tons in 2030.
For all the OECD countries, average carbon dioxide intensity in 2030 is
projected to be 296 metric tons per million dollars. OECD Europe is projected
to have the lowest carbon dioxide intensity among the OECD economies in
2030, at 241 metric tons per million dollars, followed by Mexico at 247
metric tons and Japan at 262 metric tons. (Mexico’s relatively low carbon
dioxide intensity results in large part from its projected 3.9-percent
annual GDP growth rate, the highest among the OECD countries.) Without
carbon dioxide constraints, Canada is projected to have the highest carbon
dioxide intensity of the OECD countries in 2030, at 422 metric tons per
million dollars, followed by South Korea at 396 metric tons and Australia/New
Zealand at 365 metric tons. U.S. carbon dioxide intensity in 2030 is projected
to be 339 metric tons per million dollars of GDP. The average for the entire
world is projected to fall from 494 metric tons per million dollars of
GDP in 2005 to 282 metric tons in 2030.
Emissions per Capita
Another measure of carbon dioxide intensity is emissions per person. Carbon
dioxide emissions per capita in the OECD economies are significantly higher
(about fourfold in 2005) than in the non-OECD economies (Figure 83). If
non-OECD countries consumed as much energy per capita as the OECD countries,
the projection for world carbon dioxide emissions in 2030 would be much
larger, because the non-OECD countries would consume almost four times
more energy than the current reference case estimate of 409 quadrillion
Btu. Further, given the expectation that non-OECD countries will rely heavily
on fossil fuels to meet their energy needs, the increase in carbon dioxide
emissions would be even greater.
Among the non-OECD countries, Russia has the highest projected increase
in carbon dioxide emissions per capita in the IEO2008 reference case, from
12 metric tons per person in 2005 to 17 metric tons in 2030 (Figure 84
and Table 14). A projected decline in Russia’s population, averaging 0.6
percent per year from 2005 to 2030, slows the growth in its total carbon
dioxide emissions to an average annual rate of 0.9 percent, but the population
decline leads to a higher rate of increase in emissions per capita. The
lowest levels of per capita emissions in the world are in India and Africa.
For India, emissions per capita are projected to increase by about 50 percent,
from 1.0 metric tons per person in 2005 to 1.5 in 2030. For Africa, emissions
per capita are projected to remain at about 1 metric ton per person through
2030.
The OECD countries have higher levels of carbon dioxide emissions per capita,
in part because of their higher levels of income and fossil fuel use per
capita. In the United States, emissions per capita are projected to fall slightly,
from 20 metric tons per person in 2005 to 19 metric tons in 2030 (Figure
85). Canada’s emissions per capita are projected to rise slightly, from
19 metric tons per person in 2005 to 20 metric tons in 2030, in the absence
of binding constraints on carbon dioxide emissions. In Mexico, with the
lowest level of per capita emissions among the OECD countries, an increase
from 4 metric tons in 2005 to 5 metric tons in 2030 is projected.
Other factors that can affect carbon dioxide emissions per capita include
climate (in general, more energy is used per capita for heating in colder
climates than is used for cooling in warmer climates) and population density
(densely populated countries use less energy per capita for transportation).
For example, Canada has a relatively cold climate with a low population
density, and its carbon dioxide emissions in 2005 are estimated at 19.5
metric tons per capita, whereas Japan has a more temperate climate and
a much higher population density, and its emissions in 2005 are estimated
at 9.6 metric tons per capita—about half the rate for Canada.
Alternative Macroeconomic Growth Cases
Economic growth is the most significant factor underlying the projections
for growth in energy-related carbon dioxide emissions in the mid-term,
as the world continues to rely on fossil fuels for most of its energy use.
Accordingly, projections of world carbon dioxide emissions are lower in
the IEO2008 low economic growth case and higher in the high economic growth
case.
In the high growth case, world carbon dioxide emissions are projected to
increase at an average rate of 2.1 percent annually from 2005 to 2030,
as compared with 1.7 percent in the reference case. For the OECD countries,
the projected average increase is 0.9 percent per year; for the non-OECD
countries, the average is 2.9 percent per year. In the low growth case,
world carbon dioxide emissions are projected to increase by 1.3 percent
per year, with averages of 0.2 percent per year in the OECD countries and
2.1 percent per year in the non-OECD countries (compared with 0.5 percent
and 2.5 percent, respectively, in the reference case). Total emissions
worldwide are projected to be 38.4 billion metric tons in 2030 in the low
growth case and 46.6 billion metric tons in the high growth case—21 percent
higher than projected in the low growth case (Figure 86). The projections
for emissions by fuel show similar variations across the cases.
Alternative Price Cases
The projections for carbon dioxide emissions in the IEO2008 low and high
price cases (Figure 87) show smaller variations from the reference case
than do those in the alternative macroeconomic growth cases. In 2030, as
compared with the reference case projection (42.3 billion metric tons),
total carbon dioxide emissions are projected to be higher in the low price
case (43.4 billion metric tons) and lower in the high price case (40.1
billion metric tons). Thus, there is an 8-percent difference between the
projections in the two alternative world oil price cases, as compared with
a 21-percent difference between the alternative macroeconomic growth cases.
In the alternative price cases, world oil and natural gas prices are affected
more strongly than coal prices. As a result (and in the absence of policies
to limit the use of coal), in the high price case both liquids and natural
gas lose global market share to coal relative to the reference case projection.
In the IEO2008 reference case, coal’s share of total energy use is projected
to increase to 29 percent in 2030; in the high price case, its share increases
to 30 percent; and in the low price case, its share drops to 27 percent
in 2030.
Prices have the greatest impact on world liquids consumption and the associated
carbon dioxide emissions. In the high price case, where nominal world oil
prices reach $186 per barrel in 2030, nations choose alternative fuels over liquids
wherever possible, so that liquids-related emissions total 13.1 billion
metric tons in 2030, down from 14.9 billion metric tons in the reference
case. In the low price case, world oil prices decline to $69 per barrel
in 2030, substantially lower than the $113 per barrel projected in the
reference case and providing little economic incentive for nations to turn
to other forms of energy. Consequently, liquids-related emissions in 2030
in the low price case, at 16.2 billion metric tons, are 1.3 billion metric
tons higher than projected in the reference case.
The impact of high prices on natural gas use is smaller than the impact
on liquids consumption, but a similar trend away from natural gas to other
fuels, particularly coal, is projected. In the high price case, world carbon
dioxide emissions from natural gas combustion in 2030 total 8.3 billion
metric tons, down from 8.7 billion metric tons in the reference case. In
the low price case, natural-gas-related emissions in 2030 are projected
to total 9.2 billion metric tons.
Notes and Sources
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